Afternoon all, I’m currently swapping my ignition barrel on my 300tdi. The old one worked, but it was a bit sticky and getting tired. I have come to swap it over and have found the new one has 5 terminals on it rather than the 4 on my original. Can anyone point me in the right direction as to the wiring order?
It’s made slightly trickier for me as it has an aftermarket immobiliser fitted, so not all wiring colours are OEM.

Which is your new one ?

Also look here ....

My new one is as per the one on the left in your image. Original is on the right.

So the old ones (left) used to feed the 12V to the heater plugs (S3 and early 200tdi's) and the new one (on the right) fed a voltage to a relay which powers the heater plugs.

One the same would be the simpler solution TBH

Many thanks for your help, I agree, a simpler option might be to return the purchased ignition and buy another to match my existing.

Yes, you need the correct one for your car not one for another model/year ...

as miktdish the new switch may fit etc but is probably unlike to handle the direct load of the glow plug

Thanks Gents, ive ordered a correct replacement. Very frustrating when a reputable supplier falsely sells you something that isn’t suitable for the intended vehicle.

LRWold said:

Thanks Gents, ive ordered a correct replacement. Very frustrating when a reputable supplier falsely sells you something that isn’t suitable for the intended vehicle.

Click to expand...

It may not be the suppliers fault. Over the years these vehicles tend to be modified and fitted with what was to hand so if they are just matching off a model year it might not necessarily be what is on the vehicle, and that is assuming they were all the same when they left the factory rather than made up with whatever was left over in the parts bin on a Friday afternoon.

Mine for example is a '89 TD 110. It has a discovery 200tdi engine, a discovery hi ratio transfer box, a later models disc braked slaisbury rear axle, 300tdi wiring loom and most electrical parts as also 300tdi but not all, some have little adapter looms to fit the older spec part to the later spec loom. I have over time learned the specifics of my vehicle and regularly have the conversations with suppliers that this is what I want regardless of the fact that is does not match what the computer tells them when they enter my reg. The latest was on an upgraded alternator that I had to agree to accept the liability for it not fitting because the part I was trying to order was not specc-ed for my engine let alone my vehicle. Needless to say it fitted with no issues because it was what I had fitted prior to the engine fire!